The present invention generally relates to a system and a method for determining movement of a drilling component, such as, for example, a tool, a drill bit or other wellbore device, within a wellbore.
To obtain hydrocarbons, a drilling tool is driven into the ground surface to create a borehole through which the hydrocarbons are extracted. Typically, a drill string is suspended within the borehole. The drill string has a drill bit at a lower end of sections of drill pipe. The drill string extends from the surface to the drill bit. The drill string has a bottom hole assembly (“BHA”) located proximate to the drill bit, which consists of one or more tools, such as measuring devices, power supplies, motors, stabilizers or the like.
Wellbores are drilled to locate and produce hydrocarbons. A downhole drilling tool with a drill bit at one end thereof is advanced into the ground via a drill string to form a wellbore. The drill string and the downhole tool are typically made of a series of drill pipes connected together by threads to form a long tube with the drill bit at the lower end thereof. As the drilling tool is advanced, a drilling fluid, such as mud, is pumped from a surface pit, through the drill string and the drilling tool and out the drill bit to cool the drilling tool and carry away cuttings. The fluid exits the drill bit and flows back up to the surface for recirculation through the tool. The drilling mud is also used to form a mudcake to line the wellbore.
During the drilling operation, it is desirable to provide communication between the surface and the downhole tool. Wellbore telemetry devices are typically used to allow, for example, command and/or communication signals to pass between a surface unit and the downhole tool. These signals are used to control the operation of the downhole tool and send downhole information to the surface.
Various wellbore telemetry systems may be used to establish the desired communication capabilities. Examples of such systems may include a wired drill pipe wellbore telemetry system as described in U.S. Pat. No. 6,641,434, an electromagnetic wellbore telemetry system as described in U.S. Pat. No. 5,624,051, an acoustic wellbore telemetry system as described in PCT Patent Application No. WO2004085796, the entire contents of which are hereby incorporated by reference. Other data conveyance or communication devices, such as transceivers coupled to sensors, may also be used to transmit power and/or data.
With wired drill pipe telemetry systems (“wired drill pipe”), the drill pipes that form the drill string are provided with electronics capable of passing a signal between a surface unit and the downhole tool. As shown, for example, in U.S. Pat. No. 6,641,434, such wired drill pipe telemetry systems can be provided with wires and inductive couplings that form a communication chain that extends through the drill string. The wired drill pipe is then operatively connected to the downhole tool and a surface unit for communication therewith. The wired drill pipe system is adapted to pass data received from components in the downhole tool to the surface unit and commands generated by the surface unit to the downhole tool. Further documents relating to wired drill pipes and/or inductive couplers in a drill string are as follows: U.S. Pat. Nos. 4,126,848, 3,957,118 and 3,807,502, the publication “Four Different Systems Used for MWD,” W. J. McDonald, The Oil and Gas Journal, pages 115-124, Apr. 3, 1978, U.S. Pat. No. 4,605,268, Russian Federation Published Patent Application 2140527, filed Dec. 18, 1997, Russian Federation Published Patent Application 2,040,691, filed Feb. 14, 1992, WO Publication 90/14497A2, U.S. Pat. Nos. 5,052,941, 4,806,928, 4,901,069, 5,531,592, 5,278,550, and 5,971,072.
Frequently, during drilling of a wellbore, the BHA may move down a given distance and then be withdrawn from the wellbore for any number of reasons. For example, it may be necessary or beneficial to position a wireline and logging device into the wellbore to analyze the wellbore prior to continuing to drill. In another example, it may be necessary or beneficial to replace the drill bit, a component of the BHA, or a portion of the drill string. Also, the drill string may be stuck or it may be necessary to perform casing or other wellbore operations without the BHA within the wellbore.
Accordingly, it is common for the BHA, the drill bit, and other portions of the drill string to move past the same position within the wellbore numerous times prior to completing the drilling operations of the wellbore. As a result, the wellbore may become unstable or susceptible to damage based on the repeated movement of the drill bit, BHA or other component of the drill string past a position of the wellbore. Therefore, there is a need to monitor and record the frequency in which the drill bit, the BHA or other component passes a predetermined depth of the wellbore so that an operator may identify potential drilling hazards and take corrective action, if necessary.